Indications for Insertion
Exploration for a cryptorchid testicle and the finding of testicular agenesis or atrophy is the most common indication for insertion of a testicular prosthesis. Indeed, testicular agenesis or atrophy may be present in up to 8–10% of patients who have an inguinal exploration for cryptorchidism. An implant may also be requested following testicular atrophy arising from damage of the testicular vasculature during orchidopexy, inguinal hernia repair or varicocele ligation.
A non-viable testis identified at exploration for testicular torsion or testicular trauma may also be accompanied by the insertion of a prosthesis. Certainly, all men undergoing radical orchidectomy for testicular cancer should be offered simultaneous implantation of a testicular prosthesis. Patients undergoing genital reconstruction for intersex or gender dysphoria are also candidates for testicular prosthesis implantation.
A survey of members of the Western Section of the America Urological Association in 1986 reported the indications for implantation of a testicular prosthesis over a 10-year period13 and is summarised in Table 1. This historical study shows that nearly a fifth of patients undergoing insertion of a testicular prosthesis were in men undergoing bilateral orchidectomy for advanced prostate cancer.
However, since the availability in the early 1990s of medical castration with luteinising hormone releasing hormone (LHRH) analogues, the usage of surgical castration in the management of metastatic prostate cancer has fallen dramatically; thus, this indication for implantation has fallen considerably.
Current Implants in Use
There are four companies (Nagor Ltd, Douglas, Isle of Man, UK; Mentor Medical Systems Ltd, Wantage, Oxon UK; Osteotec Plastic Surgery, Dorset, UK; and Silimed, Dieburg, Germany) that supply the majority of testicular prostheses used in the UK. Osteotec Plastic Surgery supplies the Perthese prosthesis.
Nagor prostheses are produced as silicone-gel filled and elastomer versions whereas the Silimed implant is only available in the elastomer version, which has a more solid consistency. The Perthese implant is produced in the gel-filled version; however, Mentor Medical Systems provides a re-inforced silicone elastomer version called the Soft-Solid Testicular Prosthesis (SSTP). They also provide a saline-filled prosthesis which has recently received FDA approval and is the only licensed testicular prosthesis available for common usage in the US.
The weight, shape and texture of the Mentor SSTP is designed to approximate the normal testicle and is only licensed for investigational purposes in North America. The company is currently conducting a clinical study to evaluate the safety of its SSTP; to date, 60 patients have been enrolled in up to 10 study sites and been followed up for 1 year.
The Mentor, Nagor and Perthese prostheses are produced with a suture loop to aid fixation of the implant in the scrotum’s most pendant position and reduce unnecessary movement.
Nagor and Perthese prostheses are produced in small, medium or large sizes. The Mentor saline-filled version is also available in an extra small size whereas its SSTP version is produced in five different sizes as is the Silimed implant.